78 PARASITOLOGY. 



Taenoides. 



Distribution. — Common in Europe ; not reported 

 in the United States. 



Description. — The body of the adult is white, elon- 

 gated and lanceolate shaped toward the head. It 

 tapers posteriorly and presents the general appear- 

 ance of a worm. The ventral surface is flattened ; 

 it is rounded dorsally ; the body is composed of 

 about ninety rings ; the head part is provided with 

 small booklets which enable it to hold on firmly. 

 The males are much smaller than the females. 



Animals Infested. — Adult infests dogs ; larva infest 

 cattle, sheep, etc. 



Life History. — The adult deposits the ova in the 

 nasal chambers of the dog, and they are afterward 

 expelled by the animal when sneezing ; thus the grass 

 of the pastures or other food or water become con- 

 taminated with the eggs. These eggs are taken in 

 by the intermediate host, and upon reaching the 

 stomach hatch and liberate the embryos. The em- 

 bryos are ovoid in shape, fiat below and convex 

 above, and thus somewhat resemble the Acari. 

 They are provided with two pair of legs. The head 

 extremity is furnished with a stylet-shaped boring 

 apparatus. By means of this boring apparatus they 

 find their way through the stomach or intestinal wall 

 and become located in the mesenteric lymph glands, 

 lungs or liver, where they develop into fully formed 

 larvae. This transformation requires about seven 

 months. 



Condition Produced. — The larvae thus encysted are 

 taken in by carnivorous animals, through consump- 

 tion of the affected part, or the larvae ma^ leave the 



